Panel form with removable overhang above well portion

ABSTRACT

A form for producing, by casting or molding as in concrete, a panel having a generally planar portion and a thicker portion at one edge, with a notch along the outer edge of the thicker portion. The form includes a plate conforming to one side and the edges of the panel, thus providing a well to form the thicker portion, with an adjustable overhang corresponding in contour to the notch. Reinforcement is readily placed in the mold, through the open space of the mold top. Lips extend outwardly from the opposite sidewalls of the plate to provide, respectively, striking surfaces with the upper edge of the overhang and a mounting position for the overhang. Flexing devices, which are connected between the base for the plate and the sidewalls, are mounted in a protected position beneath the lips, while the connections between the base and the underside of the plate, as by welding, are at positions spaced from the outer edges of the plate. The overhang is removable, as well as end plates which close the molding space. The end plates are removed and the overhang may be loosened before the edges of the plate are flexed to permit lifting of the cast panel from the mold, as after the concrete has initially set.

United States Patent Gordon L. Marcott 1365 Columbine St., Denver, Colo. 80206 [21] App1.No. 848,167

[22] Filed Aug. 7, 1969 [45] Patented Dec. 7, 1971 [72] Inventor [54] PANEL FORM WlTl-l REMOVABLE DVERHANG ABOVE WELL PORTION 6 Claims, 7 Drawing Figs.

[52] 11.8. CI 249/98, 249/127, 249/153, 249/165 [51 Int. Cl B28b 7/06 [50] Field of Search 249/35, 69,

70,127,163,50,66,l55, 158,165,167, 8,9, 98, 153;25/ll8.5, 120, I21 R, 131 R, 131 P,44, 118

Primary Examiner Robert D. Baldwin Attorney-Van Valkenburgh and Lowe ABSTRACT: A form for producing, by casting or molding as in concrete, a panel having a generally planar portion and a thicker portion at one edge, with a notch along the outer edge of the thicker portion. The form includes a plate conforming to one side and the edges of the panel, thus providing a well to form the thicker portion, with an adjustable overhang corresponding in contour to the notch. Reinforcement is readily placed in the mold, through the open space of the mold top. Lips extend outwardly from the opposite sidewalls of the plate to provide, respectively, striking surfaces with the upper edge of the overhang and a mounting position for the overhang. Flexing devices, which are connected between the base for the plate and the sidewalls, are mounted in a protected position beneath the lips, while the connections between the base and the underside of the plate, as by welding, are at positions spaced from the outer edges of the plate. The overhang is removable, as well as end plates which close the molding space. The end plates are removed and the overhang may be loosened before the edges of the plate are flexed to permit lifting of the cast panel from the mold, as after the concrete has initially set.

PATENTEB um Hem 3625488 I6 J ulil;

Gordon L. MarcoH INVENTOR.

A T TORNE Y5 PATENTED DEC 7197! SHET 2 W 2 FIG. 6

INVENTOR. Gordon L. Marcoff FIG. 7

A TTORNEYS PANEL FORM WITII REMOVABLE OVERI-IANG ABOVE WELL PORTION This invention relates to casting or molding forms, and more particularly to such forms which are particularly adapted to produce a panel or the like having an offset along one edge, such as the building construction panel of my copending application Ser. No. 828,073 filed May I, 1969.

The building construction panel of my aforesaid application Ser. No. 828,073 includes a planar portion which extends from one side to a point adjacent the opposite side, at which a thicker or beam portion is formed by an offset having a longitudinal notch adapted to receive the edge of a planar panel or the planar portion of a similar panel, the notch thus being in alignment with said planar portion. A reinforcement, such as wire mesh, extends within the planar portion and also into the beam portion, while a series of longitudinally extending reinforcing rods may be placed in the beam portion. These reinforcing rods in the beam portion are particularly desirable when the panel is formed from a relatively lightweight material, such as a calcium silicate hydrate product, a lightweight aerated concrete or a styrofoam composition or the like. When a more normal concrete is utilized, the reinforcing rods in the beam may be reduced in number. In casting or molding such a panel, the problems involved are numerous. For instance, to place the concrete mix or other appropriate mix in a vertical mold and then lift the mold off the formed panel requires additional structure of the mold, since only one end is open, as well as heavy lifting equipment, to separate the mold from the cast panel. Also, there is a possibility of tipping the panel over, during stripping of the mold, which is disadvantageous if the mold is stripped as soon as the concrete or other material is initially set. To permit concrete, for instance, to remain in the mold until completely set would tie up too many molds for too long a period of time. If the mold is closed and laid flat upon the planar side or one end, the difficulties in stripping the mold are also considerable. If the mold is open only at the beam side of the panel, there still remains the problem of forming the longitudinal notch in that side. Also, in order to pour the beam section most readily, the offset portion of the beam section must be below the planar section, but there still remains the problem of stripping the mold, when the mold is made to conform with the notch or offset in the beam section.

Among the objects of this invention are to provide a novel form for casting or molding an article having an offset, particularly along one edge; to provide such a form which is particularly adapted to be utilized in casting or molding a panel or the like having a notch along one edge; to provide such a form in which the extent of the notch along one offset edge is adjustable; to provide such a form which may be readily and expeditiously used in the pouring of concrete or the like thereinto, as well as when reinforcing material is placed in the form; to provide such a form which permits the leveling off of one surface of the casting or molding material, without interference; to provide such a form which may be stripped readily from the cast or molded material therein; to provide such a form from which the mold or casting may be readily removed after an initial setting, with a minimum of danger of breakage; to provide such a form which may be used numerous times; to provide such a form which may be handled readily; to provide such a fonn which is easily set up; and to provide such a form which is sturdy in construction and will withstand the rigors of hard usage.

The foregoing and additional objects, as well as the novel features of this invention, will become apparent from the description which follows, taken in conjunction with the accompanying drawings, in which:

FIG. I is a perspective view of a casting form constructed in accordance with this invention;

FIG. 2 is a condensed longitudinal section, taken along line 2-2 of FIG. I, on an enlarged scale;

FIG. 3 is an end view of the form of FIG. I, on an enlarged scale and shown without a pair of removable end plates;

FIG. 4 is a fragmentary vertical section, on a further enlarged scale, taken at one side along line 4-4 of FIG. 1;

FIG. 5 is a similar fragmentary vertical section, but taken at the opposite side along line 5-5 of FIG. 1;

FIG. 6 is a condensed side elevation, on an enlarged scale and showing the side opposite that which appears in FIG. l; and

FIG. 7 is a fragmentary, further enlarged side elevation, showing particularly a flexing device and certain associated parts which are also shown in FIG. I.

As in FIG. ll, a form constructed in accordance with the present invention may include a plate P which is contoured to the shape of one side and all or a portion of the end edges of the article to be cast or molded therein, thus including a well 9 of FIG. 3, in which an offset or beam portion of the panel heretofore described is produced. Plate P is mounted on a base B for support upon a floor or other generally horizontal surface, while a riser or overhang section is removably attached at one side of the plate P and overhangs the well 9. The ends of the space above plate P are closed by removable end plates E, while a series of flexing devices D are adapted to flex the outer edges of plate P, to separate the sides of the form from the molded or cast article, for stripping purposes. The overhang section 0 may be disconnected from the plate P, for stripping, but left in position, so that it will be tilted or rocked by flexing of the portion of plate P therebeneath. Or, the overhang section 0 may remain connected to the plate P and flexed along with it, depending upon whether or not there is any tendency for breakage of the portion of the article molded in well 9.

The plate P, as in FIG. 3, includes an upright sidewall 10, corresponding to the edge of the planar portion hereinbefore referred to, connected by a bevel II with an extended flat 12, corresponding to one side of the planar portion of such panel. The lateral extent of the flat 12 comprises the greater portion of the lateral extent of the form and, at the edge opposite sidewall 10, is connected to a depending or downtumed portion 13 which provides one side of well 9. Portion 13 is connected to a bottom I4 of the well 9, in turn connected to an opposite sidewall 15, which provides the opposite side of well 9. At each corner 16, connecting flat 12 with depending portion 13, connecting depending portion I3 with bottom 14 and connecting bottom 14 with wall 15, the form is rounded, as through a suitable arc, such as having a radius of three-fourths inch. The upper edge of sidewall 10 is connected to a generally horizontal lip 17 which extends outwardly from the sidewall and, in turn, is connected to a depending outer flange 18. On the opposite side, the upper edge of sidewall 15 is connected to a generally horizontal, outwardly extending lip 19, on which overhang section 0 is mounted and which, in turn, is connected to a depending flange 20. It will be noted that lip 17 and depending flange 18, on one side, as well as lip 19 and depending flange 20, in the opposite side, may be integral with plate P, as shown, or may be separate angular sections welded to the upper edges of the corresponding sidewalls l0 and I5.

Overhang section 0 includes an upright flange 23 having a strike edge 24 at the top and connected to a bottom flange 25, as by a corner 16'. The overhang section 0 may be reinforced by a series of triangular gussets 26, as in FIG. 1, while the respective sidewalls l0 and 15, together with the lips and depending flanges connected thereto, may be reinforced by a series of rectangular gussets 27 and 27, respectively, each having a chamfer 28 at one or more corners, to facilitate placement of the gussets and welding the same to the parts to which they are connected. Overhang section 0 is removably secured to and adjustable laterally on lip I9 by means of a series of key bolts 30, having a head 31 on the underside of the lip, as in FIG. 5, and a longitudinal slot into or out of which a key or wedge 32 may be driven. Each bolt 30 extends through lip 19 and also through a slot 33 in bottom 25 of overhang 0, so that the overhang may be adjusted laterally. When keys 32 are driven in the respective key bolt 30, they will wedge against bottom 25 and hold the overhang securely for the pouring operation, but permit the overhang to be shifted or removed entirely when the keys 32 are driven out. Each end plate E is also removably secured against the corresponding edges of plate P and the end edges of overhang 0 by a series of key bolts 30' and keys 32 which may be driven in to lock the end plates E in position or driven out to remove the end plates E.

Each of the flexing devices D is provided with a handle 35 which is turned, as between the full and dotted positions of FIG. 7, to cause the respective edges of plate P to be flexed, as about the flexure point 36 of FIG. 4 and flexure point 37 of FIG. 5. Thus, the sidewall and the bevel 11 are flexed from the full to the dotted positions of FIG. 4, along with that portion of plate P beyond the flexure point 36, while the opposite wall 15 and the adjacent portion of well bottom 14 beyond flexure point 37 will be moved from the full to the dotted positions of FIG. 5. Before the flexing devices D are actuated, of course, the end plates E are removed from the mold, as by driving out keys 32', while the overhang 0 may also be removed or loosened in position, as by driving out keys 32. The latter will permit the lip 19 to move beneath the overhang 0 and loosen the overhang from the adjacent concrete or the like. Of course, if the flexure of the overhang 0 remaining solidly affixed to the lip 19 does not tend to break the material within well 9, the overhang 0 may remain connected to the lip 19. When the panel to be formed in the mold is concrete, the panel may be removed soon after the initial setting of the concrete has taken place, i.e., such as from 20 to 28 hours, or an electrical heating device may be installed on the underside of plate P, as between flexure points 36 and 37, to reduce the time for initial setting, as to a time of about 4 to 6 hours. A sheet of polyurethane or the like is preferably placed over the molded panel, to retain heat and moisture, while a polyurethane pad may be placed beneath the electrical heating grid, to conserve heat. The temperature may be thermostatically controlled to about 140 F. for 2 hours and 160 F. for 2 to 4 hours additional. After the end plates have been removed and the overhang 0 loosened, and the plate P flexed to loosen the mold from the concrete, the overhand 0 is completely removed and set aside. The panel is then in condition to be lifted upwardly from the mold, as by lifting wires embedded in the concrete thereof and attached to the wire mesh or other reinforcing. The panel need be lifted only a short distance to clear the top of the mold and may be placed on suitable supports for further aging.

After removal of one panel from the mold, the plate P and plates E and the flange 23 and bottom 25 of overhang 0, as well as lip 19, are cleaned, as by rags soaked in solution which will not only assist in removing any concrete remaining on the surfaces, but will also coat the surfaces to minimize adherence of the next panel thereto. The wire reinforcement for the next panel may then be placed in the mold, for instance, to extend upwardly along sidewall 10, along flat 12 and down into well 9. When longitudinal reinforcing rods are placed in the beam section of the panel, which is formed in well 9, they may be attached to the wire mesh which extends into the well. The wire mesh is, of course, bent to a suitable shape and is spaced, where necessary, from any of the surfaces, as by upright or laterally extending spacing wires. The overhang 0 is next attached to lip 19, being adjusted to the desired position, and the keys 32 then driven home. Thereafter, the end plates E are secured in position by driving in keys 32'. The next panel is poured by merely filling the mold with suitable concrete or other mixture, using lip 19 and edge 24 of overhang 0 as striking surfaces, to level off the top of the concrete poured. After leveling, the concrete surface may be finished in any suitable manner.

The base B, as in FIGS. 2 and 3, includes a side angle 40 and an opposite side angle 41, bottom flanges of each extending outwardly. The upper edge of angle 41 is welded or otherwise secured to the underside of plate P, at the flexure point 37, while the upper edge of a Z-bar 42 is welded to the underside of plate P at flexure point 36. Z-bar 42 includes an angular flange 43, the lower edge of which is welded to the upper edge of angle 40 and which provides a mounting position for the flexing devices D on that side. A pair of end spreader plates 44, as in FIGS. 1 and 2, extend between the ends of angles 40 and 41, while a series of intermediate spreader plates 45, each having a short lower flange 46, also extend laterally between the angles 40 and 41, each of the plates 44 and 45 being welded to the angles and to the underside of the plate P. The corresponding ends of the plates 44 and 45, as in FIG. 3, are also contoured to fit the underside of the well 9. In addition, a series of angles 47, such as two in number, extend longitudinally beneath plate P at spaced positions from the center thereof, being received in slots 48 cut into the upper edges of the spreader plates 44 and 45. The angles 47 are, of course, welded to the underside of the plate P and also to the spreader plates 44 and 45 at the edges of the slots 48. As in FIG. 3, intennediate key bolts 30' for the end plates E are attached to and extend outwardly from the end spreader plates 44, while the outer key bolts 30' are attached to the gussets 27 and 27.

The lower ends of flexing devices D beneath overhang 0, as in FIGS. 1 and 3, are connected to horizontal channels 50, the ends of which are welded to the upright flange of angle 41 and the lower flanges of which are welded to the lower flange of angle 41. To facilitate positioning and welding of channels 50, the lower inner corner of each may be provided with a chamfer 28. A cover plate 51 may be welded to two of the channels 50 to form a box structure, as in FIG. 1, and each plate 51 provided with a hole (not shown) for attachment of a hook or cable to enable the mold to be more readily moved about, as by a crane or hoist. A pair of lifting plates 52 may be welded to angle 40, as in FIGS. 3, 4 and 6, and each provided with a hole 53, similar to the holes in plates 51, for lifting and handling purposes.

Each flexing device D, as in FIGS. 4, 5 and 7, may be mounted between a bracket 56, which at spaced positions along one side extends between and is attached, as by welding, to the underside of lip 17 and the outside of sidewall 10, the latter connection preferably being adjacent the bottom of wall 10. On the opposite side, similar brackets 56 are attached, as by welding, to the underside of lip 19 and to the outside of the opposite sidewall 15, again preferably adjacent the lower edge of the latter. The lower end of each flexing device D is mounted on an angle bracket 57 which at one side is attached, as by welding, one leg flat against the angular flange 43. At the opposite side, the ends of angle brackets 57 are attached, as by welding, to the channels 50. Each flexing device D includes a sleeve 58 having threads 59 on the outside at the upper end and interior threads at the lower end, the outside threads 59 and the interior threads being in opposite directions, such as the threads 59 being left hand and the interior threads being right hand. The inner end of handle 35 is attached, as by welding, to the sleeve 58, while the interior threads of the sleeve engage corresponding threads on a bolt or capscrew 60 which is adjustably attached to the lower inclined leg of the corresponding angle bracket 57, as by lock nuts 61 and associated washers, as shown. The exterior threads 59 engage corresponding threads on the inside of a nut 62 welded to the underside of bracket 56. As will be evident, due to the reverse relation of the exterior threads 59 and the threads of the capscrew 60, together with the corresponding relation of the interior threads engaged thereby, when the handle 35 is turned in one direction, as from the full to the dotted position of FIG. 7, the brackets 56 and 57 will be pulled together, thus flexing the outer edge of the plate means P. When the handle 35 is moved in the reverse direction, the brackets 56 and 57 will be pushed apart, thus shifting the outer edge of the plate means P to the original position. The lock nuts 61 are preferably adjusted so that the lips 17 and 19 will be parallel to the flat 12 of plate means P, with the handle 35 in the unflexed or full line position of FIG. 7.

From the foregoing, it will be evident that the present invention fulfills to a marked degree the requirements and objects hereinbefore set forth. With the overhang 0 and end plates E in position, the reinforcing may be readily placed in the mold and the mold then filled with a suitable mix. If concrete, the material may be permitted to take a preliminary set, sufficient for handling purposes, whereupon the end plates B may be removed and the overhang 0 preferably loosened. Then the flexing devices D may be actuated to flex the ends of the plate means P, in order to loosen the edges of the panel or the like from the mold. Then, the overhang 0 may be removed completely and the panel lifted in the manner described. The connection of the base B to the underside of the plate means P permits the flexing of the edges of the plate means P to be accomplished at both sides, without interference and without any tendency for any portion of the panel to be cracked or damaged by the flexing. While the edges of the plate means P are held in the flexed position, i.e., the dotted positions of FIGS. 4 and 5, the uncured panel may be lifted from the mold and placed on a suitable support for curing. When the edges of the plate means P are to be restored to the original position, the handles of flexing devices D are readily returned, as from the dotted to the full positions of FIG. 7. As soon as the overhang 0 has been removed, it may be placed in an upside down position, to facilitate cleaning and application of a parting composition to the surfaces which will engage the mold material. Also, the end plates E are readily cleaned and a parting composition applied thereto, while all molding surfaces of the plate means P are exposed for cleaning and the application of a parting composition.

The preferred construction of the base B, as shown, adequately supports the plate means P, although considerable variation may be made in the design of the base B. However, the connection of the flexing devices D between the base and the underside of the plate means P, particularly to the upright wall and opposite wall, not only produces the desired flexing of the edges of the plate means, but also positions the flexing devices D in a protected position beneath the respective lips 17 and 119. The lip 17 and the upper edge 24 of the overhang 0 provide readily accessible striking surfaces, while the upper edges of the end plates E may also be utilized as striking surfaces. The positioning of reinforcing members, such as the end spreader plates and the end gussets, provide a relatively solid position for removable attachment of the end plates. Also, all of the removable attaching devices are in positions such that no interference with either pouring or striking is produced.

It will be understood that the mold may be modified for molding or casting panels which difier in shape and exterior contour from the panels for which the form of the mold shown is particularly adapted, such as having irregularities or steps in the flat 12 or a thicker portion at each side, rather than at one side only. For the latter, it is necessary only to duplicate the well 9 and associated parts, including the overhang 0, on the opposite side.

Although a preferred embodiment of this invention has been illustrated and described and certain variations therein indicated, it will be understood that other embodiments may exist and that various changes may be made therein, all without departing from the spirit and scope of this invention.

1 claim:

I. A form for producing, by casting, molding or the like, a panel and the like having a generally planar portion, a thicker portion at one edge of the planar portion and a notch along the outer edge of said thicker portion, said form comprising:

plate means corresponding to the contour of both edges of said panel and one side of said planar portion and said thicker portion, said plate means providing a well in which said thicker portion is formed;

removable overhang means overhanging said well and corresponding to the contour of said notch;

a first longitudinally disposed lip extending laterally and outwardly from the upper outer edge of said well, said overhang means being removably mounted on said first "P;

a second longitudinally disposed lip extending laterally and outwardly from the opposite upper edge of said plate means;

said plate means provides an upright wall at one edge connected to said second lip, a bevel connecting said wall with a flat comprising the majority of the width of said plate means, a downturn at the opposite edge of said flat and forming one side of said well, a bottom for said well, an opposite end wall fonning the opposite side of said well and arcuate corners respectively between said flat and said downturn, between said downturn and said well bottom and between said well bottom and said opposite end wall;

an outer flange depending from the outer edge of each of said first and second lips;

a series of gussets extending transversely to and attached respectively to said first lip, said opposite end wall and the corresponding depending flange, and to said second lip, said upright wall and the corresponding depending flange, including a gusset at each end of each said lip; and

means closing the ends of the space above said plate means.

2. A form for producing, by casting or the like, a panel having an outer planar surface, an inner planar surface in spaced parallelism with the outer surface to define the panel thickness, squared, transverse ends, a longitudinal side edge at one side, a longitudinal thickened portion at the other side which is inwardly offset from the inner planar surface and a side notch at the outer side of the thickened portion having a depth corresponding to the thickness of the panel, which comprises:

a plate means corresponding to the contour of the first said side edge, the inner planar surface, the thickened portion and the outer side edge of the thickened portion which terminates at the edge of the aforesaid side notch, the plate means at the thickened portion defining a well wherein the thickened portion of the panel is fonned;

a longitudinally disposed lip extending laterally and outwardly from the first-mentioned side edge at the level of the outer planar surface of the panel to define a striking surface for leveling material poured into the form to the level of the outer planar surface;

a second longitudinally disposed lip extending laterally and outwardly from the outer side edge of the well, at the level of the inner planar surface of the panel, and in the plane of that portion of the plate means defining the aforesaid inner planar surface;

an angular member having a base flange removably mounted upon the aforesaid second lip to overhang the well to define a face of the aforesaid panel notch and having an upright flange extending from the overhanging edge of the base flange and projecting upwardly to the level of the outer planar surface of the panel to define the base of the notch and a striking edge cooperating with the opposite, first-mentioned lip for leveling material poured into the form;

a frame means for rigidly holding the plate means at the inner planar surface portion and at the floor of the well;

a retractable holding means carried on the frame means for holding the side edge portion of the plate means and the opposite thickened portion when a panel is being poured into the forms, but to retract to permit these portions to flex when the panel is to be removed from the form; and

means for closing the ends of the forms.

3. In the organization defined in claim 2, wherein:

said frame means holds the plate means at the inner planar surface portion and at the floor of the well with outer edge portions of the inner planar surface portion and of the floor of the well being cantilever suspended from the frame means, whereby to facilitate flexing of the side edge portion of the plate means and the opposite thickened portion.

Al. A form as defined in claim 1, wherein:

said overhang means comprises an upright flange facing said plate means, a bottom flange resting on said first lip, transverse gussets extending between said flanges and a series of transverse slots in said bottom flange disposed between said gussets;

a series of upright members positioned to extend through said slots are attached to said second lip; and

means for locking said bottom flange of said overhang means against said first lip is associated with each said upright member.

5, A fonn as defined in claim 4, including:

a base for supporting said form, which comprises:

first and second supporting members disposed longitudinally beneath said well and said second lip, respectively, said first member having an upright flange whose upper edge is attached to the underside of said well bottom at a position spaced from said opposite end wall;

a series of channellike members extending laterally and outwardly from said first supporting member;

a series of brackets extending between said second lip and said upright wall and between said first lip and said opposite end wall;

a member having an angular flange attached to the upper edge of said second supporting member and attached at the opposite edge to the underside of said flat at a position spaced from said bevel;

an angular bracket attached to said angular flange and an angular bracket attached to said channel members, beneath each said first-mentioned bracket;

a flexing device extending between each said first-mentioned bracket and the corresponding angular bracket;

a series of spreaders, including a spreader at each end, extending transversely between said first and second supporting members and attached thereto and to the underside of said plate means; and

a series of longitudinal reinforcing members extending between said end spreaders and attached to the underside of said plate means.

6. A form as defined in claim 5, wherein:

said end closing means comprise a plate detachably connected to each end of said form, said end plates having holes therein;

a series of members outstanding from said end spreaders and said end gussets positioned to engage said holes in said end plates; and

means for locking said end plates against the ends of said form and associated with said outstanding members.

a a w a a 

1. A form for producing, by casting, molding or the like, a panel and the like having a generally planar portion, a thicker portion at one edge of the planar portion and a notch along the outer edge of said thicker portion, said form comprising: plate means corresponding to the contour of both edges of said panel and one side of said planar portion and said thicker portion, said plate means providing a well in which said thicker portion is formed; removable overhang means overhanging said well and corresponding to the contour of said notch; a first longitudinally disposed lip extending laterally and outwardly from the upper outer edge of said well, said overhang means being removably mounted on said first lip; a second longitudinally disposed lip extending laterally and outwardly from the opposite upper edge of said plate means; said plate means provides an upright wall at one edge connected to said second lip, a bevel connecting said wall with a flat comprising the majority of the width of said plate means, a downturn at the opposite edge of said flat and forming one side of said well, a bottom for said well, an opposite end wall forming the opposite side of said well and arcuate corners respectively Between said flat and said downturn, between said downturn and said well bottom and between said well bottom and said opposite end wall; an outer flange depending from the outer edge of each of said first and second lips; a series of gussets extending transversely to and attached respectively to said first lip, said opposite end wall and the corresponding depending flange, and to said second lip, said upright wall and the corresponding depending flange, including a gusset at each end of each said lip; and means closing the ends of the space above said plate means.
 2. A form for producing, by casting or the like, a panel having an outer planar surface, an inner planar surface in spaced parallelism with the outer surface to define the panel thickness, squared, transverse ends, a longitudinal side edge at one side, a longitudinal thickened portion at the other side which is inwardly offset from the inner planar surface and a side notch at the outer side of the thickened portion having a depth corresponding to the thickness of the panel, which comprises: a plate means corresponding to the contour of the first said side edge, the inner planar surface, the thickened portion and the outer side edge of the thickened portion which terminates at the edge of the aforesaid side notch, the plate means at the thickened portion defining a well wherein the thickened portion of the panel is formed; a longitudinally disposed lip extending laterally and outwardly from the first-mentioned side edge at the level of the outer planar surface of the panel to define a striking surface for leveling material poured into the form to the level of the outer planar surface; a second longitudinally disposed lip extending laterally and outwardly from the outer side edge of the well, at the level of the inner planar surface of the panel, and in the plane of that portion of the plate means defining the aforesaid inner planar surface; an angular member having a base flange removably mounted upon the aforesaid second lip to overhang the well to define a face of the aforesaid panel notch and having an upright flange extending from the overhanging edge of the base flange and projecting upwardly to the level of the outer planar surface of the panel to define the base of the notch and a striking edge cooperating with the opposite, first-mentioned lip for leveling material poured into the form; a frame means for rigidly holding the plate means at the inner planar surface portion and at the floor of the well; a retractable holding means carried on the frame means for holding the side edge portion of the plate means and the opposite thickened portion when a panel is being poured into the forms, but to retract to permit these portions to flex when the panel is to be removed from the form; and means for closing the ends of the forms.
 3. In the organization defined in claim 2, wherein: said frame means holds the plate means at the inner planar surface portion and at the floor of the well with outer edge portions of the inner planar surface portion and of the floor of the well being cantilever suspended from the frame means, whereby to facilitate flexing of the side edge portion of the plate means and the opposite thickened portion.
 4. A form as defined in claim 1, wherein: said overhang means comprises an upright flange facing said plate means, a bottom flange resting on said first lip, transverse gussets extending between said flanges and a series of transverse slots in said bottom flange disposed between said gussets; a series of upright members positioned to extend through said slots are attached to said second lip; and means for locking said bottom flange of said overhang means against said first lip is associated with each said upright member.
 5. A form as defined in claim 4, including: a base for supporting said form, which comprises: first and second supporting members disposed longitudinally beneath said well and saId second lip, respectively, said first member having an upright flange whose upper edge is attached to the underside of said well bottom at a position spaced from said opposite end wall; a series of channellike members extending laterally and outwardly from said first supporting member; a series of brackets extending between said second lip and said upright wall and between said first lip and said opposite end wall; a member having an angular flange attached to the upper edge of said second supporting member and attached at the opposite edge to the underside of said flat at a position spaced from said bevel; an angular bracket attached to said angular flange and an angular bracket attached to said channel members, beneath each said first-mentioned bracket; a flexing device extending between each said first-mentioned bracket and the corresponding angular bracket; a series of spreaders, including a spreader at each end, extending transversely between said first and second supporting members and attached thereto and to the underside of said plate means; and a series of longitudinal reinforcing members extending between said end spreaders and attached to the underside of said plate means.
 6. A form as defined in claim 5, wherein: said end closing means comprise a plate detachably connected to each end of said form, said end plates having holes therein; a series of members outstanding from said end spreaders and said end gussets positioned to engage said holes in said end plates; and means for locking said end plates against the ends of said form and associated with said outstanding members. 